Aldurazyme

Patient Information

Patients should be counseled that allergic reactions may occur during ALDURAZYME treatment, including life-threatening anaphylaxis. Premedication and reduction of infusion rate may alleviate those allergic reactions associated with the infusion. The appropriate length of post-infusion monitoring is to be determined by the treating physician based on the individual patient’s clinical status and infusion history [see WARNINGS AND PRECAUTIONS].

Patients should be advised to report any adverse reactions experienced while on ALDURAZYME treatment.

It is unknown how ALDURAZYME affects women during pregnancy, labor and delivery or while nursing, as no adequate and well-controlled clinical studies have been conducted in these patient populations [see Use In Specific Populations].

The full benefits of ALDURAZYME may not be evident for several months to years of treatment. To maintain treatment benefit, ALDURAZYME should be administered on a weekly basis as indicated.

Patients should be informed that a registry for MPS I patients has been established in order to better understand the MPS I disease and to track clinical outcomes of patients with MPS I over time. Patients should be encouraged to participate, and advised that their participation is voluntary and may involve long-term followup.  Information regarding the registry program may be found at www.MPSIregistry.com or by calling (800) 745-4447.

Description

ALDURAZYME (laronidase) is a polymorphic variant of the human enzyme αliduronidase that is produced by recombinant DNA technology in a Chinese hamster ovary cell line. α-l-iduronidase (glycosaminoglycan α-l-iduronohydrolase, EC 3.2.1.76) is a lysosomal hydrolase that catalyzes the hydrolysis of terminal α-l-iduronic acid residues of dermatan sulfate and heparan sulfate.

Laronidase is a glycoprotein with a molecular weight of approximately 83 kD. The predicted amino acid sequence of the recombinant form, as well as the nucleotide sequence that encodes it, are identical to a polymorphic form of human α-L-iduronidase. The recombinant protein is comprised of 628 amino acids after cleavage of the N-terminus and contains 6 N-linked oligosaccharide modification sites. Two oligosaccharide chains terminate in mannose-6-phosphate sugars. ALDURAZYME has a specific activity of approximately 172 U/mg.

ALDURAZYME, for IV infusion, is supplied as a sterile, nonpyrogenic, colorless to pale yellow, clear to slightly opalescent solution that must be diluted prior to administration in 0.9% Sodium Chloride Injection, USP. The solution in each vial contains a nominal laronidase concentration of 0.58 mg/mL and a pH of approximately 5.5. The extractable volume of 5.0 mL from each vial provides 2.9 mg laronidase, 43.9 mg sodium chloride, 63.5 mg sodium phosphate monobasic monohydrate, 10.7 mg sodium phosphate dibasic heptahydrate, and 0.05 mg polysorbate 80. ALDURAZYME does not contain preservatives; vials are for single use only.

ALDURAZYME® (laronidase) is indicated for patients with Hurler and Hurler-Scheie forms of Mucopolysaccharidosis I (MPS I) and for patients with the Scheie form who have moderate to severe symptoms. The risks and benefits of treating mildly affected patients with the Scheie form have not been established.

ALDURAZYME has been shown to improve pulmonary function and walking capacity. ALDURAZYME has not been evaluated for effects on the central nervous system manifestations of the disorder.

Dosage And Administration

Recommended Dose

The recommended dosage regimen of ALDURAZYME is 0.58 mg/kg of body weight administered once weekly as an intravenous (IV) infusion. Pretreatment is recommended 60 minutes prior to the start of the infusion and may include antihistamines, antipyretics, or both [see Instructions for Use below and WARNINGS AND PRECAUTIONS].

Each vial of ALDURAZYME provides 2.9 milligrams (mg) of laronidase in 5.0 milliliters (mL) of solution and is intended for single use only. Do not use the vial more than one time. The concentrated solution for infusion must be diluted with 0.9% Sodium Chloride Injection, USP, to a final volume of 100 mL or 250 mL, using aseptic techniques. The final volume of the infusion is determined by the patient’s body weight. Patients with a body weight of 20 kg or less should receive a total volume of 100 mL. Patients with a body weight greater than 20 kg should receive a total volume of 250 mL. For patients with underlying cardiac or respiratory compromise and weighing up to 30 kg, physicians may consider diluting ALDURAZYME in a volume of 100 mL and administering at a decreased infusion rate [see Instructions for Use below, WARNINGS AND PRECAUTIONS and ADVERSE REACTIONS].

Instructions for Use

Prepare and use ALDURAZYME according to the following steps. Use aseptic techniques. Prepare ALDURAZYME using low-protein-binding containers and administer with a low-protein-binding infusion set equipped with an in-line, low-protein-binding 0.2 micrometer (μm) filter. There is no information on the compatibility of diluted ALDURAZYME with glass containers.

1. Determine the number of vials to be diluted based on the patient’s weight and the recommended dose of 0.58 mg/kg, using the following equation:
   Patient’s weight (kg) x 1 mL/kg of ALDURAZYME = Total mL ALDURAZYME
   Total mL ALDURAZYME ÷ 5 mL per Vial = Total number of Vials.
2. Round up to the next whole vial. Remove the required number of vials from the refrigerator to allow them to reach room temperature. Do not heat or microwave vials.
3. Before withdrawing the ALDURAZYME from the vial, visually inspect each vial for particulate matter and discoloration. The ALDURAZYME solution should be clear to slightly opalescent and colorless to pale yellow. Some translucency may be present in the solution. Do not use if the solution is discolored or if there is particulate matter in the solution.
4. Withdraw and discard a volume of the 0.9% Sodium Chloride Injection, USP, from the infusion bag, equal to the volume of ALDURAZYME concentrate to be added.
5. Slowly withdraw the calculated volume of ALDURAZYME from the appropriate number of vials using caution to avoid excessive agitation. Do not use a filter needle, as this may cause agitation. Agitation may denature ALDURAZYME, rendering it biologically inactive.
6. Slowly add the ALDURAZYME solution to the 0.9% Sodium Chloride Injection, USP, using care to avoid agitation of the solutions. Do not use a filter needle.
7. Gently rotate the infusion bag to ensure proper distribution of ALDURAZYME. Do not shake the solution.
8. The entire infusion volume (100 mL for patients weighing 20 kg or less and 250 mL for patients weighing greater than 20 kg) should be delivered over approximately 3 to 4 hours. The initial infusion rate of 10 μg/kg/hr may be incrementally increased every 15 minutes during the first hour, as tolerated, until a maximum infusion rate of 200 μg/kg/hr is reached. The maximum rate is then maintained for the remainder of the infusion (2-3 hours), as outlined in Tables 1 and 2.
9. Administer the diluted ALDURAZYME solution to patients using a low-protein-binding infusion set equipped with a low-protein-binding 0.2 μm in-line filter.

Table 1: Incremental Rates for 100 mL ALDURAZYME® Infusion (For use with Patients Weighing 20 kg or Less)

Table 2: Incremental Rates for 250 mL ALDURAZYME® Infusion (For use with Patients Weighing Greater than 20 kg)

ALDURAZYME does not contain any preservatives; therefore, after dilution with saline, the infusion bags should be used immediately. If immediate use is not possible, the diluted solution should be stored refrigerated at 2° to 8°C (36° to 46°F) for up to 36 hours. Other than during infusion, room temperature storage of diluted solution is not recommended. Any unused product or waste material should be discarded and disposed of in accordance with local requirements.

ALDURAZYME must not be administered with other medicinal products in the same infusion. The compatibility of ALDURAZYME in solution with other products has not been evaluated.

How Supplied

Dosage Forms And Strengths

ALDURAZYME is supplied as a sterile solution in 5 mL vials (2.9 mg per 5 mL).

Storage And Handling

ALDURAZYME is supplied as a sterile solution in single-use, clear Type I glass 5 mL vials, containing 2.9 mg laronidase per 5 mL solution. The closure consists of a siliconized butyl stopper and an aluminum seal with a plastic flip-off cap.

NDC 58468-0070-1, 5 mL vial

Refrigerate vials of ALDURAZYME at 2° to 8°C (36° to 46°F). Do not freeze or shake. Protect from light. Do not use ALDURAZYME after the expiration date on the vial. This product contains no preservatives.

BioMarin Pharmaceutical Inc., Novato, CA 94949. Distributed by: Genzyme Corporation, 500 Kendall Street, Cambridge, MA 02142. Revised April 2013.

Clinical Trials Experience

Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in clinical practice.

The most serious adverse reactions reported with ALDURAZYME treatment during clinical trials were anaphylactic and allergic reactions. Most adverse reactions reported in clinical trials were considered diseaserelated and unrelated to study drug. The most common adverse reactions were infusion reactions. The frequency of infusion reactions decreased over time with continued use of ALDURAZYME, and the majority of reactions were classified as being mild to moderate in severity. Most infusion reactions requiring intervention were ameliorated with slowing of the infusion rate, temporarily stopping the infusion, with or without administering additional treatments including antihistamines, antipyretics, or both.

Clinical Trials in Patients 6 Years and Older

A 26-week, double-blind, placebo-controlled clinical study (Study 1) of ALDURAZYME was conducted in 45 patients with MPS I, ages 6 to 43 years old, gender evenly distributed (N=23 females and 22 males). Of these 45 patients, 1 was clinically assessed as having Hurler form, 37 Hurler-Scheie, and 7 Scheie. Patients were randomized to receive either 0.58 mg/kg IV of ALDURAZYME per week for 26 weeks or placebo. All patients were treated with antipyretics and antihistamines prior to the infusions. Infusion reactions were reported in 32% (7 of 22) of ALDURAZYME-treated patients. The most commonly reported infusion reactions regardless of treatment group were flushing, pyrexia, headache, and rash. Flushing occurred in 5 patients (23%) receiving ALDURAZYME; the other reactions were less frequent. Less common infusion reactions included angioedema (including face edema), hypotension, paresthesia, feeling hot, hyperhidrosis, tachycardia, vomiting, back pain, and cough. Other reported adverse reactions included bronchospasm, dyspnea, urticaria and pruritus.

Table 3 enumerates adverse reactions and selected laboratory abnormalities that occurred during the placebocontrolled study (Study 1) that were reported in at least 2 patients more in the ALDURAZYME group than in the placebo group.

Table 3: Summary of Adverse Reactions that Occurred in 2 Patients More in the ALDURAZYME® Group than in the Placebo Group in the 26-Week Placebo-controlled Study (Study 1)

All 45 patients who completed the placebo-controlled study (Study 1) continued treatment in an open-label, uncontrolled extension study (Study 2). All patients received ALDURAZYME 0.58 mg/kg of body weight once weekly for up to 182 weeks. The most serious adverse reactions reported with ALDURAZYME infusions in Study 2 were anaphylactic and allergic reactions [see WARNINGS AND PRECAUTIONS]. The most common adverse reactions requiring intervention were infusion reactions reported in 49% (22 of 45) of patients treated with ALDURAZYME. The most commonly reported infusion reactions included rash (13%), flushing (11%), pyrexia (11%), headache (9%), abdominal pain or discomfort (9%), and injection site reaction (9%). Less commonly reported infusion reactions included nausea (7%), diarrhea (7%), feeling hot or cold (7%), vomiting (4%), pruritus (4%), arthralgia (4%), and urticaria (4%). Additional common adverse reactions included back pain and musculoskeletal pain.

Clinical Trials in Patients 6 Years and Younger

Study 3 was a 52-week, open-label, uncontrolled study of 20 MPS I patients, ages 6 months to 5 years old (at enrollment). Sixteen patients were clinically assessed as having the Hurler form, and 4 had the Hurler-Scheie form. All 20 patients received ALDURAZYME at 0.58 mg/kg of body weight once weekly for 26 weeks and up to 52 weeks. All patients were treated with antipyretics and antihistamines prior to the infusions.

The most commonly reported serious adverse events (regardless of relationship) reported with ALDURAZYME infusions in Study 3 were otitis media (20%), and central venous catheterization required for ALDURAZYME infusion (15%).

The nature and severity of infusion reactions were similar between the older and less severely affected patients in Studies 1 and 2, and the younger, more severely affected patients in Study 3. The most commonly reported adverse reactions in Study 3 were infusion reactions reported in 35% (7 of 20) of patients and included pyrexia (30%), chills (20%), blood pressure increased (10%), tachycardia (10%), and oxygen saturation decreased (10%). Other commonly reported infusion reactions occurring in ≥ 5% of patients were pallor, tremor, respiratory distress, wheezing, crepitations (pulmonary), pruritus, and rash.

Immunogenicity

In clinical trials, 99 of 102 patients (97%) treated with ALDURAZYME were positive for IgG antibodies to ALDURAZYME. No correlation was demonstrated between the presence of IgG anti-ALDURAZYME antibodies and therapeutic response (6 MWT and FVC) or the occurrence of allergic reactions. Potential for antibody neutralization of cellular uptake has not been assessed. No consistent association was demonstrated between the presence of antibodies that neutralize enzymatic activity and therapeutic response.

The data reflect the percentage of patients whose test results were considered positive for antibodies to ALDURAZYME using a specific enzyme-linked immunosorbent assay (ELISA) and confirmed by radioimmunoprecipitation (RIP). ALDURAZYME IgG antibodies were reported as titers. Drug-specific antibody was detected in 42 of the 45 patients (93.3%) treated in Study 1 and Study 2. The mean time to seroconversion was 51 days in patients 6 years and older. In Study 3, all patients (100%) 5 years old or younger developed IgG antibodies against ALDURAZYME with a mean time to seroconversion of 26 days [see Clinical Studies for the Study populations].

Nine patients in Study 1 and Study 2, collectively, who experienced severe infusion reactions were tested for ALDURAZYME-specific IgE antibodies and complement activation. IgE testing was performed by ELISA, and complement activation was measured by the Quidel Enzyme Immunoassay. One of the nine patients had an anaphylactic reaction consisting of urticaria and airway obstruction and tested positive for both ALDURAZYME-specific IgE binding antibodies and complement activation. None of the patients in the openlabel clinical study of patients 5 years old or younger (Study 3) tested positive for IgE.

Other allergic reactions were also seen in patients receiving ALDURAZYME [see ADVERSE REACTIONS].

In the postmarketing setting, approximately 1% of patients experienced severe or serious infusion allergic reactions and tested positive for IgE. Of these IgE-positive patients, some have discontinued treatment, but some have been successfully re-challenged. The clinical significance of IgE antibodies has not been established.

As with all the therapeutic proteins, there is potential for immunogenicity. The incidence of antibody formation is highly dependent on the sensitivity and specificity of the assay. Additionally, the observed incidence of antibody (including neutralizing antibody) positivity in an assay may be influenced by several factors including assay methodology, sample handling, timing of sample collection, concomitant medications, and underlying disease. For these reasons, comparison of the incidence of antibodies to ALDURAZYME with the incidence of antibodies to other products may be misleading.

Postmarketing Experience

The following adverse reactions have been identified during post approval use of ALDURAZYME. Because these reactions are reported voluntarily from a population of uncertain size, it is not always possible to reliably estimate their frequency or establish a causal relationship to drug exposure.

In postmarketing experience with ALDURAZYME, severe and serious infusion reactions have been reported, some of which were life-threatening, including anaphylactic shock [see BOXED WARNING and WARNINGS AND PRECAUTIONS] and laryngeal edema.

Adverse reactions resulting in death reported in the postmarketing setting with ALDURAZYME treatment included cardiorespiratory arrest, respiratory failure, cardiac failure, and pneumonia. These events have been reported in MPS I patients with significant underlying disease.

Additional adverse reactions included fatigue, edema peripheral, erythema and cyanosis.

There have been a small number of reports of extravasation in patients treated with ALDURAZYME. There have been no reports of tissue necrosis associated with extravasation.

Drug Interactions

No information provided.

Included as part of the PRECAUTIONS section.

Precautions

Anaphylaxis and Allergic Reactions

[see BOXED WARNING]

Anaphylaxis and severe allergic reactions have been observed in patients during or up to 3 hours after ALDURAZYME infusions. Some of these reactions were life-threatening and included respiratory failure, respiratory distress, stridor, tachypnea, bronchospasm, obstructive airways disorder, hypoxia, hypotension, bradycardia, and urticaria. If anaphylactic or other severe allergic reactions occur, immediately discontinue the infusion of ALDURAZYME and initiate appropriate medical treatment. Caution should be exercised if epinephrine is being considered for use in patients with MPS I due to the increased prevalence of coronary artery disease in these patients. Interventions have included resuscitation, mechanical ventilatory support, emergency tracheotomy, hospitalization, and treatment with inhaled beta-adrenergic agonists, epinephrine, and IV corticosteroids [see ADVERSE REACTIONS].

In clinical studies and postmarketing safety experience with ALDURAZYME, approximately 1% of patients experienced severe or serious allergic reactions. In patients with MPS I, pre-existing upper airway obstruction may have contributed to the severity of some reactions. Due to the potential for severe allergic reactions, appropriate medical support should be readily available when ALDURAZYME is administered. Because of the potential for recurrent reactions, some patients who experience initial severe reactions may require prolonged observation.

The risks and benefits of re-administering ALDURAZYME following an anaphylactic or severe allergic reaction should be considered. Extreme care should be exercised, with appropriate resuscitation measures available, if the decision is made to re-administer the product.

Acute Respiratory Complications Associated with Administration

Patients with an acute febrile or respiratory illness at the time of ALDURAZYME infusion may be at greater risk for infusion reactions. Careful consideration should be given to the patient’s clinical status prior to administration of ALDURAZYME and consider delaying ALDURAZYME infusion. One patient with acute bronchitis and hypoxia experienced increased tachypnea during the first ALDURAZYME infusion that resolved without intervention. The patient’s respiratory symptoms returned within 30 minutes of completing the infusion and responded to bronchodilator therapy. Approximately 6 hours after the infusion, the patient experienced coughing, then respiratory arrest, and died.

Sleep apnea is common in MPS I patients. Evaluation of airway patency should be considered prior to initiation of treatment with ALDURAZYME. Patients using supplemental oxygen or continuous positive airway pressure (CPAP) during sleep should have these treatments readily available during infusion in the event of an infusion reaction, or extreme drowsiness/sleep induced by antihistamine use.

Risk of Acute Cardiorespiratory Failure

Caution should be exercised when administering ALDURAZYME to patients susceptible to fluid overload, or patients with acute underlying respiratory illness or compromised cardiac and/or respiratory function for whom fluid restriction is indicated. These patients may be at risk of serious exacerbation of their cardiac or respiratory status during infusions. Appropriate medical support and monitoring measures should be readily available during ALDURAZYME infusion, and some patients may require prolonged observation times that should be based on the individual needs of the patient [see ADVERSE REACTIONS].

Infusion Reactions

Because of the potential for infusion reactions, patients should receive antipyretics and/or antihistamines prior to infusion. If an infusion reaction occurs, regardless of pretreatment, decreasing the infusion rate, temporarily stopping the infusion, or administering additional antipyretics and/or antihistamines may ameliorate the symptoms [see ADVERSE REACTIONS].

Nonclinical Toxicology

Carcinogenesis, Mutagenesis, Impairment of Fertility

Studies to assess the mutagenic and carcinogenic potential of laronidase have not been conducted.

Laronidase at IV doses up to 3.6 mg/kg (6.2 times the human dose) was found to have no effect on the fertility and reproductive performance of male and female rats.

Use In Specific Populations

Pregnancy

Pregnancy Category B

A developmental toxicity study has been performed in rats at doses up to 6.2 times the human dose and has revealed no evidence of impaired fertility or harm to the fetus due to ALDURAZYME. However, there are no adequate and well-controlled studies of ALDURAZYME in pregnant women. Because animal reproduction studies are not always predictive of human response, this drug should be used during pregnancy only if clearly needed.

Pregnant women with MPS I should be encouraged to enroll in the MPS I Registry. For more information, visit www.MPSIregistry.com or call (800) 745-4447 [see PATIENT INFORMATION].

Nursing Mothers

It is not known whether the drug is excreted in human milk. Because many drugs are excreted in human milk, caution should be exercised when ALDURAZYME is administered to a nursing woman.

Nursing mothers with MPS I should be encouraged to enroll in the MPS I Registry [see PATIENT INFORMATION].

Pediatric Use

The safety and effectiveness of ALDURAZYME was assessed in a 52-week, open-label, uncontrolled clinical study in 20 patients with MPS I, ages 6 months to 5 years old, and was found to be similar to the safety and effectiveness of ALDURAZYME in pediatric patients 6 to 18 years, and adults [see ADVERSE REACTIONS and Clinical Studies].

Geriatric Use

Clinical studies of ALDURAZYME did not include patients aged 65 and over. It is not known whether they respond differently from younger patients.

There have been no reports of overdose with ALDURAZYME. In clinical studies, a small number of patients received doses up to 1.2 mg/kg body weight once weekly or 1.8 mg/kg body weight every other week. Adverse events reported in patients receiving 1.2 mg/kg body weight once weekly or 1.8 mg/kg body weight every other week were similar to the adverse events reported by patients treated with 0.58 mg/kg body weight once weekly.

Contraindications

None.

Mechanism of Action

Mucopolysaccharide storage disorders are caused by the deficiency of specific lysosomal enzymes required for the catabolism of glycosaminoglycans (GAG). Mucopolysaccharidosis I (MPS I) is characterized by the deficiency of α-L-iduronidase, a lysosomal hydrolase which catalyzes the hydrolysis of terminal α-L-iduronic acid residues of dermatan sulfate and heparan sulfate. Reduced or absent α-L-iduronidase activity results in the accumulation of the GAG substrates, dermatan sulfate and heparan sulfate, throughout the body and leads to widespread cellular, tissue, and organ dysfunction.

The rationale of ALDURAZYME therapy in MPS I is to provide exogenous enzyme for uptake into lysosomes and increase the catabolism of GAG. ALDURAZYME uptake by cells into lysosomes is most likely mediated by the mannose-6-phosphate-terminated oligosaccharide chains of laronidase binding to specific mannose-6- phosphate receptors.

Because many proteins in the blood are restricted from entry into the central nervous system (CNS) by the blood brain barrier, effects of intravenously administered ALDURAZYME on cells within the CNS cannot be inferred from activity in sites outside the CNS. The ability of ALDURAZYME to cross the blood brain barrier has not been evaluated in animal models or in clinical studies.

Pharmacodynamics

The pharmacodynamic effect of ALDURAZYME was assessed by reductions in urinary GAG levels. The responsiveness of urinary GAG to dosage alterations of ALDURAZYME is unknown, and the relationship of urinary GAG to other measures of clinical response has also not been established [see Clinical Studies].

Pharmacokinetics

The pharmacokinetics of laronidase were evaluated in 6 year old or older patients (N=10 to 12) with MPS I who received 0.58 mg/kg of body weight once weekly of ALDURAZYME as a 4-hour infusion in the placebocontrolled clinical study (Study 1). After the 1st, 12th, and 26th weekly infusions, the mean maximum plasma concentrations (Cmax) ranged from 1.2 to 1.7 μg/mL for the 3 time points. The mean area under the plasma concentration-time curve (AUC∞) ranged from 4.5 to 6.9 μg • hour/mL. The mean volume of distribution (Vz) ranged from 0.24 to 0.60 L/kg. Mean plasma clearance (CL) ranged from 1.7 to 2.7 mL/min/kg, and the mean elimination half-life (t½) ranged from 1.5 to 3.6 hours.

Most patients who received once weekly infusions of ALDURAZYME in Study 1 developed antibodies to laronidase by Week 12. Between Weeks 1 and 12, increases in the plasma clearance of laronidase were observed in some patients and appeared to be proportional to the antibody titer. At Week 26, plasma clearance of laronidase was comparable to that at Week 1, in spite of the continued and, in some cases, increased titers of antibodies.

The pharmacokinetics of laronidase were evaluated in 6 year old or younger patients (N=7 to 9) with MPS I disease who received 0.58 mg/kg of body weight once weekly of ALDURAZYME as a 4-hour infusion in the open label clinical study (Study 3). After the 26th infusion, the 95% confidence interval of the geometric mean values of PK parameters ranged from 0.6 to 1.6 μg/mL for the maximum plasma concentrations (Cmax), from 1.3 to 4.4 μg • hour/mL for area under the plasma concentration-time curve (AUC∞), from 0.12 to 0.56 L/kg for volume of distribution (Vz), from 2.2 to 7.7 mL/min/kg for plasma clearance (CL), and from 0.3 to 1.9 hours for elimination half-life (t½).

Clinical Studies

The safety and efficacy of ALDURAZYME were assessed in three clinical studies.

Clinical Studies in Patients 6 Years and Older

Study 1 was a randomized, double-blind, placebo-controlled study in 45 patients with MPS I, ages 6 to 43 years old, including 1 patient with the Hurler form, 37 patients with Hurler-Scheie form, and 7 patients with Scheie form of MPS I. All patients had a baseline percent predicted forced vital capacity (FVC) less than or equal to 77%. Patients received ALDURAZYME at 0.58 mg/kg of body weight once weekly or placebo once weekly for 26 weeks. All patients were treated with antipyretics and antihistamines prior to each infusion.

The primary efficacy outcome assessments were percent predicted FVC and distance walked in 6 minutes (6- minute walk test). After 26 weeks, patients treated with ALDURAZYME showed improvement in percent predicted FVC and in 6-minute walk test compared to placebo-treated patients (see Table 4).

Table 4: Primary Efficacy Outcomes in the Placebo-controlled Study (Study 1)

Evaluations of bioactivity were changes in liver size and urinary GAG levels. Liver size and urinary GAG levels decreased in patients treated with ALDURAZYME compared to patients treated with placebo. No patient in the group receiving ALDURAZYME reached the normal range for urinary GAG levels during this 6-month study.

Study 2 was a 182-week, open-label, uncontrolled extension study of all 45 patients who completed Study 1. Patients received ALDURAZYME at 0.58 mg/kg body weight once weekly. For patients treated with ALDURAZYME, the mean increase in 6-minute walk test distance was maintained for an additional 182 weeks through completion of Study 2.

At the end of Study 2, the decrease in mean urinary GAG was similar to the decrease in urinary GAG reported in ALDURAZYME-treated patients at the end of Study 1. The relationship of urinary GAG to other measures of clinical response has not been established.

Clinical Studies in Patients 6 Years and Younger

Study 3 was a 52-week, open-label, uncontrolled clinical study in 20 patients with MPS I, ages 6 months to 5 years old (at enrollment), including 16 patients (80%) with the Hurler form and 4 patients (20%) with the Hurler-Scheie form. All 20 patients received ALDURAZYME at 0.58 mg/kg of body weight once weekly for 26 weeks. After 26 weeks of treatment, 16 patients continued to receive 0.58 mg/kg of body weight once weekly through Week 52, and 4 patients received 1.16 mg/kg of body weight once weekly from Week 26 through Week 52.

Reduction in mean urinary GAG was demonstrated at Week 13 and was maintained through Week 52. No patient receiving ALDURAZYME reached the normal range for urinary GAG levels during this 52-week study. Changes in urinary GAG levels in children 6 years and younger were similar to changes reported in older patients in Studies 1 and 2 (6 through 43 years old). The relationship of urinary GAG to other measures of clinical response has not been established.